Yes, 5-card spade is almost automatic for the person bidding it. But it's not an almost automatic inference for partner who hears a 1S opening bid. Formalising it, and making the slight adjustment of bidding 4333 as 1C, improves the information partner gets from a 1S bid. It means "<=7 LTC, 5+ spades, no four-card suit unless the holding is actually 6+ spades." And that means a NT rebid can only be some permutation of 5332.
1S takes up a lot of bidding space, so it's good that it gives a lot of information.
no subject
Date: 2013-01-23 11:22 am (UTC)1S takes up a lot of bidding space, so it's good that it gives a lot of information.